[CON-05] Complete `resource_credits` Soroban smart contract

[yusuftomilola]

Overview

The resource_credits contract enables an on-chain credit ledger for resource usage (printing, meeting room minutes, amenities) but is currently unimplemented. This is the blockchain layer for the credit/hour packs feature.

Context

• Language: Rust 2021 edition, Soroban SDK (no_std)
• access_control contract governs who can issue credits — only hub admin should mint
• Credits are fungible units (represented as i128) that can be issued and spent

Tasks

• Implement issue_credits(member_address, amount, issued_by) — admin mints credit units to a member's balance
• Implement spend_credits(member_address, amount, resource_id) — deducts credits; panics if balance insufficient
• Implement get_balance(member_address) → i128 — returns current balance
• Implement get_transaction_history(member_address) → Vec of credit events (issue/spend with timestamp and resource_id)
• Enforce access control: only addresses with admin role (via access_control) can call issue_credits
• Add contract tests covering: issue, spend, insufficient balance rejection, balance query, history query

Files to Modify / Create

• contracts/resource_credits/src/ (all source files)

[heymide]

@heymide has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I can take this on. I've gone through the details and will provide a well-tested solution aligned with the project standards.

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[devdeen213]

@devdeen213 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi! I’d love to take this issue on if it’s still available. I have experience with JavaScript and open source contributions, and I’m confident I can work through the requirements. Please feel free to assign it to me, thanks!

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[grantfox-oss]

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[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox as part of the Official Campaign campaign!

@devdeen213's PR #1241 was approved and merged by @yusuftomilola.

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👏 Great work, @devdeen213! Keep contributing to DistinctCodes.

[drips-wave]

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